Lactoferrin in intrauterine infection, human parturition, and rupture of fetal membranes

OBJECTIVE: Lactoferrin is an iron-binding protein with antimicrobial proper ties. This study was undertaken to determine whether amniotic fluid concent rations of this protein change with gestational age, infection, labor, and rupture of membranes. STUDY DESIGN: This cross-sectional study included women who underwent trans abdominal amniocentesis (n = 268) in the following groups: (1) mid trimeste r of pregnancy; (2) preterm labor who delivered at term, preterm labor who delivered preterm with intra-amniotic infection, and preterm labor who deli vered preterm without intra-amniotic infection; (3) preterm premature ruptu re of membranes in the presence or absence of intra-amniotic infection, (4) term with intact membranes not in labor, in labor, and in labor with intra -amniotic infection, and (5) premature rupture of membranes at term not in labor. In addition, lactoferrin concentrations were determined in maternal plasma and cord brood of patients at term not in labor. Lactoferrin concent ration was measured with an immunoassay. RESULTS: (1) Lactoferrin was detectable in 85.4% (229/268) of amniotic flui d samples, not detectable in all fluid obtained in the mid trimester, and d etectable in all maternal and cord plasma samples. (2) The concentration of lactoferrin increased with advancing gestational age (r = 0.68; P < .0001) . (3) Intra-amniotic infection was associated with significant increases in amniotic fluid lactoferrin concentrations in patients with preterm labor ( no intra-amniotic infection median, 1641.2 ng/mL; range, <1.24-35,090.0 ng/ mL; vs intra-amniotic infection median, 3833.6 ng/mL; range, 746.0-47,020.0 ng/mL; P < .001), term labor (no intra-amniotic infection median, 2085.8 n g/mL; range, 425.0-23,230.0 ng/mL; vs intra-amniotic infection median, 5627 .0 ng/mL; range, <1.24-19,220.0 ng/mL; P < .001), and preterm premature rup ture of membranes (no intra-amniotic infection median. 2190 ng/mL; range, < 1.24-7456.1 ng/mL; vs intra-amniotic infection median. 3449.3 ng/mL; range, <1.24-83,600.0; P < .01). (4) Spontaneous labor at term but not preterm wa s associated with a significant decrease in amniotic fluid lactoferrin conc entration (P < .05). (5) Spontaneous term parturition was associated with a significant increase in umbilical cord plasma lactoferrin concentration (P < .005). CONCLUSION: (1) Intra-amniotic infection was consistently associated with d ramatically increased concentrations of lactoferrin in amniotic fluid. (2) Term parturition was associated with a significant increase in lactoferrin concentration in the fetal compartment (umbilical cord blood) and a decreas e in the amniotic compartment. We propose that lactoferrin is part of the r epertoire of host defense mechanisms against intra-amniotic infection.